The four main types of access control credentials are:
- Something You Know
Information only the user knows, such as a password, PIN, or security question answer. - Something You Have
A physical item the user possesses, like a keycard, smartphone, RFID tag, or security token. - Something You Are
Biometric data unique to the user, such as a fingerprint, facial recognition, iris scan, or voice recognition. - Somewhere You Are
Access based on the user’s location, determined through IP address, GPS, or network access point.
These credentials are often combined in multi-factor authentication systems for stronger security.